A known method of effecting the fluidizing of solid particles at high temperatures is to use wind boxes closed off by a grid comprising a series of vertical fluidizing tubes immersed in a vault of refractory blocks. This type of grid has a number of disadvantages. For example, such a grid is sensitive to expansion differences of the constituent materials so that it is difficult to seal. The interstices in the grid allow a certain quantity of fluidizing air to pass or permit the escape of a portion of the solid particles to be fluidized thereby causing gradual erosion of the grid. At the same time, such grids do not allow for replacement of the tubes to modify the distribution of the fluidizing gas in terms of the material to be fluidized or when they are worn out.
It is therefore an object of this invention to provide for a grid construction that will overcome these disadvantages.